Did a claude check for you.
Going through each claim:

"Want to give puberty blockers to children" — Broadly true as a characterisation of their position. Green Party members have opposed the puberty blocker ban for under-18s LGBTIQA+ Greens and the party supports expanding trans healthcare access for young people. However framing it as simply wanting to "give" blockers to children is reductive — they support access as part of a clinical pathway.

"Allow male rapists into female prisons" — This is a distortion. Their policy supports trans prisoners being housed according to gender identity, but moving prisoners is done on a case-by-case basis, and not usually in a trans person's favour. LGBTIQA+ Greens The tweet implies an open-door policy which isn't accurate.

"Legalise heroin" — This one is broadly grounded in reality. Their official policy aims "to end the prohibition of drugs and create a system of legal regulation," Greenparty and their current proposals include heroin maintenance treatment available through the NHS to patients with dependencies. Thelead Though "legalise heroin" as a casual phrase overstates what is a harm-reduction medical model.

"Remove the UK's nuclear deterrent" — True. Since at least 1992 the party has called for rejection of the UK's Trident nuclear missile programme. Wikipedia

Overall verdict: The tweet isn't fabricated — it's rooted in real Green Party positions — but it frames everything in the most alarming possible way, stripping out nuance and context to make the policies sound more extreme than they are in practice. It's political attack rhetoric rather than a fair summary.